Commerzbank AG has sued four banks in the United States, claiming that they failed to properly monitor billions of dollars in toxic mortgage-backed securities acquired by the German lender before the 2008 financial crisis.

Bank of New York Mellon Corp and units of Deutsche Bank AG, Wells Fargo & Co and HSBC Holdings Plc were named in the lawsuits filed on Wednesday and Thursday in Manhattan federal court.

BNY Mellon was the trustee for over $1 billion in mortgage-backed securities bought by Commerzbank and $1.3 billion of investments tied to a collateralized debt obligation, Millstone II CDO, court documents showed.